In addition, general routing resources, including clocks, buses, general-purpose routing, high-speed routing, etc. (also not shown in FIG. 1), are providedthroughout the FPGA layout to programmably interconnect the various elements within FPGA 100.The layout of an FPGA, such as FPGA 100 of FIG. 1, comprises multiple instances of a limited number of different types of blocks of circuitry.